From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 1/2] extcon: extcon-dra7xx: Add extcon driver for USB ID detection Date: Tue, 20 Aug 2013 10:53:35 -0600 Message-ID: <52139F0F.6090507@wwwdotorg.org> References: <1376648029-30659-1-git-send-email-george.cherian@ti.com> <1376648029-30659-2-git-send-email-george.cherian@ti.com> <52127284.6030506@wwwdotorg.org> <521312CC.8060003@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from avon.wwwdotorg.org ([70.85.31.133]:37198 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345Ab3HTQxk (ORCPT ); Tue, 20 Aug 2013 12:53:40 -0400 In-Reply-To: <521312CC.8060003@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: George Cherian Cc: balbi@ti.com, myungjoo.ham@samsung.com, cw00.choi@samsung.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, grant.likely@linaro.org, rob@landley.net, ian.campbell@citrix.com, mark.rutland@arm.com, pawel.moll@arm.com, rob.herring@calxeda.com, linux-omap@vger.kernel.org, linux-usb@vger.kernel.org, bcousson@baylibre.com On 08/20/2013 12:55 AM, George Cherian wrote: > Hi Stephen, > > Thanks for your review. > > On 8/20/2013 1:01 AM, Stephen Warren wrote: > >> On 08/16/2013 04:13 AM, George Cherian wrote: >>> Adding extcon driver for USB ID detection to dynamically >>> configure USB Host/Peripheral mode. >>> diff --git >>> a/Documentation/devicetree/bindings/extcon/extcon-dra7xx.txt >>> b/Documentation/devicetree/bindings/extcon/extcon-dra7xx.txt >>> +EXTCON FOR DRA7xx >>> + >>> +Required Properties: >> Please at lest explain what a DRA7xxx is, and the purpose of the HW >> module this binding describes. > > DRA7xx is the SoC name and the USB VID detection is implemented via gpio's > Basically it does only ID detection via GPIO and there is no VBUS > detection in h/w. If there's no SoC-specific HW, then the binding has nothing to do with the SoC; it's entirely generic. I think instead, you need to define a generic "gpio-usb-vid" binding instead. Otherwise, ever SoC that doesn't have explicit USB VID detection HW is going to re-invent the exact same binding, with pointless differences, rather than using a single generic binding. >>> + - compatible : Should be "ti,dra7xx-usb" >> >> If this is a USB VID detector rather than a full USB host controller, >> then "usb" in the binding is a bit over-reaching. Perhaps "-usb-vid" or >> "-usb-vid-detector" would be more accurate. > > This will be renamed to dra7xx-extcon. So no, that rename doesn't sound correct. >>> + - gpios : phandle to ID pin and interrupt gpio. >> >> Why does the interrupt line need to be included in a list of GPIOs? > > ID pins are connected to pcf8575, and the pcf8575's interrupt line is > inturn connected to > gpio bank6 pin 11, we use this gpio interrupt to detect the ID pin change. In that case, the PCF8575 node needs to be a GPIO controller and an IRQ controller, as does the driver for the PCF8575. This binding should have a single entry in the gpios property, and the driver can call gpio_to_irq() on that so it knows which IRQ to request.